You need to hide Exchange Online mailbox from address list and have AD synchronization in place, but no local Exchange.
You then extend Active Directory schema by using local Exchange installation with setup.exe /prepareschema switch.
Next, you are fire up refresh directory schema in AD Connect, and do full AD sync, and...
No, msExchHiddenFromAddressList attribute is not syncing, even if it is set in AD account attributes and seen on AD Connect connector.
If you have made all the previous steps, then probably your AD account has mailnickname attribute not set
After fill it with proper data (alias), and do another AD Connect AD sync , you can see your msExchHiddenFromAddressList synced at last.